The changes in the vitamin C content in vegetables due to solar drying were measured in green sweet pepper, broccoli and Japanese radish. Compared with content per edible portion, vitamin C content in all vegetables increased after drying. However, compared with content per dry matter, vitamin C content in all of vegetables decreased after drying. Ascorbic acid is oxidized to dehydroascorbic acid by enzymatic or non-enzymatic reactions. The quantitative ratio of dehydroascorbic acid increased in all vegetables by drying. The increase in the quantitative ratio of DHAA shows that the freshness of vegetables is lowered.